New material development for large engine springs

Force Technology has recently extended its product range to include “Valve Quality, High Tensile, Silicon Chrome Vanadium” (SiCrV) up to 14mm diameter for use in large springs typically for use on engine valve and fuel injection in large engines and other high duty applications.

Developments in production techniques have recently resulted in high quality Silicon Chrome Vanadium becoming available in larger wire diameters. The tensile strength is approximately 10% higher than conventional silicon chrome wires, allowing for a more highly stressed springs with 10% lower mass or improved fatigue life.

The superior specification wire is also “shaved”, “super clean” and eddy current tested to ensure the optimum performance. Shaving ensures the defects that collect on the surface are removed before drawing to maximise surface quality. The super clean raw rod ensures the harmful effects of non-metallic inclusions are kept to a minimum using the latest steel producing technologies.

Using this grade, fuel injection springs of wire diameter 12mm have been produced with an outside diameter of 48mm, giving a incredibly tight spring index of 3.0 (mean diameter/wire diameter). This is believed to be a world first for large diameter high tensile wire with such a high fatigue life requirement.

Dave Fielding, Design Manager commented “Many of the high duty components we supply require very high cycle fatigue lives of over 30,000 hours. This material is a major step forward, in our ability to meet our customers’ ever more demanding emission requirements, by allowing faster valve accelerations and increasing common rail pressures.”

Using the latest manufacturing processes, Force Technology supply global customers with the highest quality springs for use in applications including the world’s biggest cruise liners, railway locomotives, power generation and large mining trucks.

Our unrivalled experience and focus on optimising surface residual stress guarantees the best in fatigue life, along with consistency of performance and product capability.

If you would like further information from Force Technology on their extensive product range please contact our experienced engineering team at

The addition of  Vanadium to the Silicon Chrome alloy increases the tensile strength by approximately 10% to over 1800 MPa giving improved fatigue life and improved relaxation properties. Accordingly weight savings and space reduction of 10% or significantly improved fatigue life are possible.

The team at Force Technology have been working with valve quality SiCrV alloys below wire diameter 6.50mm for a significant number of years. The availability of the new grade above this size range is a major addition to our product range.

Wire Specification

  • Silicon Chrome Vanadium SiCrV – Valve Quality
  • EN10270-2 VD SiCrV
    • Wire Diameter 6.50mm to 15.00mm
    • Super-clean raw rod
    • Eddy current tested
    • Shaving optional

Mechanical Properties

Min Wire Dia mm Max Wire Dia mm Min Tensile Mpa Max Tensile MPa
6.51 8.00 1860 2010
8.01 10.00 1910 2060
10.01 12.00 1880 1980
12.01 13.50 1850 1950
13.51 14.00 1820 1920

Chemical Properties

Chemical Composition
C Si Cr V Mn P S Cu
0.50-0.70 1.25-1.65 0.50-1.00 0.10-0.25 0.50-0.80 Max 0.02 Max 0.02 Max 0.06